Photophysical properties of 7-hydroxyflavanone: Quantum chemical calculations and experimental studies

In this work the photophysical properties of 7-hydroxyflavanone in acetonitrile, ethanol and methanol have been studied. The quantum chemical calculations as well as the experimental measurements have been performed. The absorption and emission spectra have been obtained for 7-hydroxyflavanone dissolved in acetonitrile, ethanol and methanol. Emission spectrum of 7-hydroxyflavanone in studied solvents is characterized by one band with maximum at about 360 nm in the case of acetonitrile and 370 nm in the case of ethanol and methanol solvent. Moreover, it was found that normalized fluorescence spectra do not show significant dependence on excitation wavelength. It can be interpreted as evidence that just fluorophores of one species cause emission. Additionally, the molar extinction coefficients have been determined for 7-hydroxyflavanone. It is equal to about 11.6 × 10³ M^-1·cm^-1 at 270 nm, about 11.2 × 10³ M^-1·cm^-1 at 277 nm and about 12.0 × 10³ M^-1·cm^-1 at 275 nm for 7-hydroxyflavanone dissolved in acetonitrile, ethanol and methanol, respectively. Moreover, the total electronic energies and dipole moments have been found using by quantum chemical calculations. The dipole moment of 7-hydroxyflavanone neutral form in the ground state equals about 2.72 D, 2.70 D and 2.71 D for the case of acetonitrile, ethanol and methanol solvents, respectively. The dipole moment in the singlet-excited state equals about 4.24 D, 4.21 D and 4.23 D for the case of acetonitrile, ethanol and methanol solvents, respectively.